MAPPING AND CARTOGRAPHY OF THE ICY SATURNIAN SATELLITES USING 
CASSINI-ISS IMAGES 
Th. Roatsch 3 ' *, M. Wählisch 3 , A. Hoffmeister 3 , F. Schölten 3 , K.-D. Matz 3 , B. Giese 3 , R. Wagner 3 , E. Kersten 3 , G. Neukum b , 
and C. Poreo c 
d Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany - thomas.roatsch@dlr. 
b Remote Sensing of the Earth and Planets, Freie Universität Berlin, Germany 
c CICLOPS/Spaee Science Institute, Boulder, CO 
Commission IV, WG IV/7 
KEY WORDS: Satum, Icy Satellites, Cassini, Planetary Mapping 
ABSTRACT: 
The Saturnian system contains more than 50 satellites of different sizes. This paper deals with the mapping and the cartography of 
the so-called medium-sized icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus, and Phoebe. The Cassini spacecraft 
arrived at Saturn on July 1, 2004 and finished until now 65 orbits around Saturn. The Cassini Imaging Science Subsystem (ISS) took 
thousands of images of the icy satellites both in high resolution during close flybys and medium resolution during more distant 
observations. These image data are the baseline for local high-resolution mosaics and for global maps of all seven medium-sized 
satellites. The imaging team suggested new names for prominent features on the basis of these global maps. The nomenclature had 
to be approved by the International Astronomical Union (IAU). The global mosaics of Phoebe, Enceladus, Dione, and Tethys are the 
basis for high-resolution maps and atlases that consists of 15 tiles. The Phoebe map (1:1,000,000) and the Enceladus atlas 
(1:500,000) are available to the public through the Imaging Team's website [http://ciclops.org/maps] and the Planetary Data System 
[http://pds.jpl.nasa.gov]. 
1. INTRODUCTION 
The Saturnian system contains 56 satellites of different sizes. 
This paper deals with the mapping of the so-called medium 
sized icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, 
Iapetus, and Phoebe. 
The ISS consists of two framing cameras. The narrow angle 
camera is a reflecting telescope with a focal length of 2000mm 
and a field of view of 0.351. The wide-angle camera is a 
refractor with a focal length of 200mm and a field of view of 
3.51. Each camera is outfitted with a large number of spectral 
filters which, taken together, span the electromagnetic spectrum 
from 0.2 to 1.1 m m. At the heart of each camera is a charged 
coupled device (CCD) detector consisting of a 1024 square 
array of pixels, each 12 mm on a side. The data system allows 
many options for data collection, including choices for on-chip 
summing and data compression. The stated objective of the ISS 
is to obtain global coverage for all medium-sized icy satellites 
with a resolution better than 1 km/pixel and high-resolution 
images (Porco et al., 2004). This goal is being achieved with 
image sequences obtained during close flybys supplemented by 
images from greater distances to complete the coverage. Close 
flybys of all medium sized satellites except Mimas are 
performed during the nominal mission of the Cassini spacecraft 
until July 1, 2008. The first flybys during the mission were 
those of Phoebe in June 2004 and Iapetus in December 2004 
followed by three flybys of Enceladus in February, March, and 
July 2005 (see Table 1) (Porco et al., 2005, 2006). 
Unfortunately, the Cassini ISS has not yet imaged the northern 
high latitude regions because they are shrouded in seasonal 
darkness and will not be illuminated by the Sun until later in the 
decade when the Cassini extended mission begins. Fortunately, 
the Voyager camera was able to take images from these regions 
during its flyby in the early 1980’s. We thus used Voyager 
images to fill the North polar gaps in the global mosaics. 
Details of the image processing will be described in chapter 2, 
examples of mosaics and basemaps will be shown in chapter 3, 
followed by chapter 4 about the Icy satellite atlases. 
Table 1. Icy satellites flybys 2004-2008 
Satellite 
Flyby Date 
Flyby Altitude 
[km] 
Phoebe 
11 June 2004 
2,070 
Iapetus 
31 Dec. 2005 
123,400 
Enceladus 
17 Feb. 2005 
1,260 
Enceladus 
09 March 2005 
500 
Enceladus 
14 July 2005 
170 
Mimas 
02 Aug. 2005 
61,150 
Tethys 
24 Sep. 2005 
1500 
Hyperion 
26 Sep 2005 
500 
Dione 
11 Oct. 2005 
500 
Rhea 
26 Nov. 2005 
500 
Tethys 
27 June 2007 
18,417 
Tethys 
29 Aug. 2007 
55,500 
Rhea 
30 Aug. 2007 
5,738 
Iapetus 
10 Sep. 2007 
1,6151 
Dione 
30 Sep. 2007 
44,349 
Enceladus 
12 March 2008 
50 
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